The present invention concerns a process for determination of the last intermediate node of a pathway consisting of a minimum number of nodes, within a network comprising numerous nodes interconnected by means of a number of links. It concerns also a process for establishing a routing table for each node of the network as well as a general routing table enabling routing across the network of both data communications between interconnected computers, and telephonic communications between interconnected switchboard systems. The invention is useful in a communications network constituted by a number of geographically separated nodes connected by communication lines.
In order to route a message between two distant nodes, it is often necessary to traverse various other nodes. This creates the problem of determining the pathway comprising the least possible number of intermediate links or nodes, and, in particular, the addresses of those nodes. Moreover, recognizing that certain nodes or internodal links may be saturated or out of service at any given time, it is necessary to be able to establish and to modify a communications routing table.
Modular networks having a configuration easily adaptable to specific requirements are known, as described for example in French Pat. No. 2 366 754. Also known are systems that establish waiting files in the event of saturation, as described for example in French Pat. No. 2 453 557. These networks are not adaptable to accommodate changes in their characteristics.
In French Pat. No. 2 320 022, a process is described to establish addresses of through lines by means of communications establishment telegrams transmitted by relay stations. According to this process, each time communications are established, corresponding telegrams pass through the entire communications network, with only the length of the telegrams being controlled. For this reason, the desired destination point is reached by at least one telegram. Such a process takes into account the state of each point of the network, but it suffers from the disadvantage of requiring the transmission of telegrams over the entire network, which may contribute to the saturation of the network, and it does not enable easy determination of the shortest pathway to use.
The present invention has as its goal to overcome these disadvantages.